Adjustable left atrial appendage implant

ABSTRACT

Disclosed is an adjustable occlusion device for use in a body lumen such as the left atrial appendage. The occlusion device is removably carried by a deployment catheter. The device may be enlarged or reduced to facilitate optimal placement or removal. Methods are also disclosed.

This is a divisional of U.S. patent application Ser. No. 10/033,371,filed Oct. 19, 2001 and issued as U.S. Pat. No. 7,044,134 on May 16,2006, which is a continuation-in-part of U.S. patent application Ser.No. 09/435,562, filed Nov. 8, 1999 and issued as U.S. Pat. No. 7,128,073on Oct. 31, 2006, the disclosures of which are incorporated in theirentirety herein by reference.

BACKGROUND OF THE INVENTION

Embolic stroke is the nation's third leading killer for adults, and is amajor cause of disability. There are over 700,000 strokes per year inthe United States alone. Of these, roughly 100,000 are hemoragic, and600,000 are ischemic (either due to vessel narrowing or to embolism).The most common cause of embolic stroke emanating from the heart isthrombus formation due to atrial fibrillation. Approximately 80,000strokes per year are attributable to atrial fibrillation. Atrialfibrillation is an arrhythmia of the heart that results in a rapid andchaotic heartbeat that produces lower cardiac output and irregular andturbulent blood flow in the vascular system. There are over five millionpeople worldwide with atrial fibrillation, with about four hundredthousand new cases reported each year. Atrial fibrillation is associatedwith a 500 percent greater risk of stroke due to the condition. Apatient with atrial fibrillation typically has a significantly decreasedquality of life due, in part, to the fear of a stroke, and thepharmaceutical regimen necessary to reduce that risk.

For patients who develop atrial thrombus from atrial fibrillation, theclot normally occurs in the left atrial appendage (LAA) of the heart.The LAA is a cavity which looks like a small finger or windsock andwhich is connected to the lateral wall of the left atrium between themitral valve and the root of the left pulmonary vein. The LAA normallycontracts with the rest of the left atrium during a normal heart cycle,thus keeping blood from becoming stagnant therein, but often fails tocontract with any vigor in patients experiencing atrial fibrillation dueto the discoordinate electrical signals associated with AF. As a result,thrombus formation is predisposed to form in the stagnant blood withinthe LAA.

Blackshear and Odell have reported that of the 1288 patients withnonrheumatic atrial fibrillation involved in their study, 221 (17%) hadthrombus detected in the left atrium of the heart. Blackshear J L, OdellJ A., Appendage Obliteration to Reduce Stroke in Cardiac SurgicalPatients With Atrial Fibrillation. Ann Thorac. Surg., 1996.61(2):755-9.Of the patients with atrial thrombus, 201 (91%) had the atrial thrombuslocated within the left atrial appendage. The foregoing suggests thatthe elimination or containment of thrombus formed within the LAA ofpatients with atrial fibrillation would significantly reduce theincidence of stroke in those patients.

Pharmacological therapies for stroke prevention such as oral or systemicadministration of warfarin or the like have been inadequate due toserious side effects of the medications and lack of patient compliancein taking the medication. Invasive surgical or thorascopic techniqueshave been used to obliterate the LAA, however, many patients are notsuitable candidates for such surgical procedures due to a compromisedcondition or having previously undergone cardiac surgery. In addition,the perceived risks of even a thorascopic surgical procedure oftenoutweigh the potential benefits. See Blackshear and Odell, above. Seealso Lindsay B D., Obliteration of the Left Atrial Appendage: A ConceptWorth Testing, Ann Thorac. Surg., 1996.61(2):515.

Despite the various efforts in the prior art, there remains a need for aminimally invasive method and associated devices for reducing the riskof thrombus formation in the left atrial appendage.

SUMMARY OF THE INVENTION

There is provided in accordance with one aspect of the present inventionan adjustable occlusion device deployment system, for implanting anocclusion device within a tubular structure in the body. The systemcomprises an occlusion device, movable between a reduced cross sectionand an enlarged cross section. A deployment catheter is provided,releasably attached to the occlusion device. A releasable lock forretaining the occlusion device is provided on the catheter, along with acore, for changing the cross section of the occlusion device.

The occlusion device comprises an expandable frame, which may have atleast two and preferably at least about six spokes. In one embodiment,the occlusion device has sixteen spokes. Each spoke is moveable from anaxial orientation when the occlusion device is in a reduced crosssection, to an inclined orientation when the occlusion device is in anenlarged cross section. Preferably, at least one tissue attachmentelement is provided on the occlusion device.

In accordance with another aspect of the present invention, there isprovided an occlusion device for occluding a tubular body structure. Thedevice comprises a plurality of spokes, which are moveable between anaxial orientation and an inclined orientation. A threaded aperture iscarried by the device, and a stop surface is also carried by the device.A threaded core is rotatable within the aperture, to cause the core tocontact the stop surface and axially elongate the device.

In accordance with a further aspect of the present invention, there isprovided an implantable device. The device comprises a radiallyenlargeable frame having a proximal end and a distal end. A proximallyfacing stop surface is provided within the frame, and a threadedaperture is positioned in the frame, proximally of the stop surface.Distal axial advancement of a threaded core through the threadedaperture distally advances the stop surface, thereby axially elongatingand radially reducing the implantable device. In one embodiment, theimplantable device is an occlusion device. In an alternate embodiment,the implantable device is a filter.

In accordance with another aspect of the present invention, there isprovided an occlusion device implantation system. The system comprises adeployment catheter, having an elongate flexible body with a proximalend and a distal end. An anti-rotation lock is provided on the body. Arotatable core extends axially through the body, and a radiallyexpandable implant is releasably connected to the distal end of thebody.

In accordance with a further aspect of the present invention, there isprovided a method of implanting a device in the left atrial appendage.The method comprises the steps of providing a deployment catheter,having an elongate flexible body with a proximal end and a distal end, acontrol on the proximal end and a device removably carried by the distalend. At least a portion of the device is positioned within the leftatrial appendage, and the control is manipulated to enlarge the deviceunder positive force.

In one application of the invention, the manipulating step comprisesrotating the control. In general, the device comprises an expandableframe having at least two and preferably at least about six spokes. Eachspoke is movable from an axial orientation when the device is in areduced cross section to an inclined orientation when the device is inan enlarged cross section.

In accordance with a further aspect of the present invention, there isprovided a method of removing a device having tissue anchors thereon,from a site in the body. The method comprises the steps of positioning aretrieval catheter with respect to the device such that the anchors arewithin a flared distal end on the retrieval catheter. The diameter ofthe flared distal end is reduced, with the anchors therein. Theretrieval catheter is thereafter removed from the site. In one aspect ofthe method, the reducing step comprises positioning the flared distalend within an outer tubular sleeve.

In accordance with a further aspect of the present invention, there isprovided a retrieval catheter for retrieving a device from animplantation site within the body. The retrieval catheter comprises anelongate flexible body, having a proximal end and a distal end. Agrasping structure is provided on or carried within the flexible body,for grasping the device, and a flared tubular sleeve is provided forsurrounding at least a portion of the device. An outer tubular sleeve,for surrounding the flared tubular sleeve is also provided. The flaredtubular sleeve in one embodiment comprises a plurality of petals, whichare movable between an axial orientation and an inclined orientation.

Further features and advantages of the present invention will becomeapparent to those of ordinary skill in the art in view of the detaileddescription of preferred embodiments which follows, when consideredtogether with the attached drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an occlusion device in accordance withthe present invention.

FIG. 2 is a side elevational view of the occlusion device shown in FIG.1.

FIG. 3 is a perspective view of an alternate embodiment of the presentinvention.

FIG. 4 is a side elevational view of the embodiment shown in FIG. 3.

FIG. 5 is a perspective view of a further embodiment of the presentinvention.

FIG. 6 is a side elevational view of the embodiment of FIG. 5.

FIG. 7 is a perspective view of a support structure for a furtherocclusion device in accordance with the present invention.

FIG. 7A is a side elevational view of the device of FIG. 7.

FIG. 7B is an end view taken along the line 7B-7B of FIG. 7A.

FIG. 8 is a schematic illustration of an inflatable balloon positionedwithin the occlusion device of FIG. 7.

FIG. 9 is a schematic view of a pull string deployment embodiment of theocclusion device of FIG. 7.

FIGS. 10 and 11 are side elevational schematic representations ofpartial and complete barrier layers on the occlusion device of FIG. 7.

FIG. 12 is a side elevational schematic view of an alternate occlusiondevice in accordance with the present invention.

FIG. 13 is a schematic view of a bonding layer mesh for use in forming acomposite barrier membrane in accordance with the present invention.

FIG. 14 is an exploded cross sectional view of the components of acomposite barrier member in accordance with the present invention.

FIG. 15 is a cross sectional view through a composite barrier formedfrom the components illustrated in FIG. 14.

FIG. 16 is a top plan view of the composite barrier illustrated in FIG.15.

FIG. 17 is a schematic view of a deployment system in accordance withthe present invention.

FIG. 17A is an enlarged view of a releasable lock in an engagedconfiguration.

FIG. 17B is an enlarged view as in FIG. 17A, with the core axiallyretracted to release the implant.

FIG. 18 is a perspective view of a flexible guide tube for use in theconfigurations of FIG. 17 and/or FIG. 19.

FIG. 19 is a schematic view of an alternate deployment system inaccordance with the present invention.

FIGS. 19A-19B illustrate a removal sequence for an implanted device inaccordance with the present invention.

FIG. 20 is a schematic cross sectional view through the distal end of aretrieval catheter having an occlusion device removably connectedthereto.

FIG. 20A is a side elevational schematic view of the system illustratedin FIG. 20, with the occlusion device axially elongated and radiallyreduced.

FIG. 20B is a side elevational schematic view as in FIG. 20A, with theocclusion device drawn part way into the delivery catheter.

FIG. 20C is a schematic view as in FIG. 20B, with the occlusion deviceand delivery catheter drawn into a transeptal sheath.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 and 2, there is illustrated one embodiment of theocclusion device 10 in accordance with the present invention. Althoughthe present invention will be described primarily in the context of anocclusion device, the present inventors also contemplate omitting thefabric cover or enlarging the pore size to produce implantable filtersor other devices which are enlargeable at a remote implantation site.

The occlusion device 10 comprises an occluding member 11 comprising aframe 14 and a barrier 15. In the illustrated embodiment, the frame 14comprises a plurality of radially outwardly extending spokes 17 eachhaving a length within the range of from about 0.5 cm to about 2 cm froma hub 16. In one embodiment, the spokes have an axial length of about1.5 cm. Depending upon the desired introduction crossing profile of thecollapsed occlusion device 10, as well as structural strengthrequirements in the deployed device, anywhere within the range of fromabout 3 spokes to about 40 spokes may be utilized. In some embodiments,anywhere from about 12 to about 24 spokes are utilized, and, 18 spokesare utilized in one embodiment.

The spokes are advanceable from a generally axially extendingorientation such as to fit within a tubular introduction catheter to aradially inclined orientation as illustrated in FIG. 1 and FIG. 2following deployment from the catheter. In a self-expandable embodiment,the spokes are biased radially outwardly such that the occlusion memberexpands to its enlarged, implantation cross-section under its own biasfollowing deployment from the catheter. Alternatively, the occlusionmember may be enlarged using any of a variety of enlargement structuressuch as an inflatable balloon, or a catheter for axially shortening theocclusion member, as is discussed further below.

Preferably, the spokes comprise a metal such as stainless steel,Nitinol, Elgiloy, or others which can be determined through routineexperimentation by those of skill in the art. Wires having a circular orrectangular cross-section may be utilized depending upon themanufacturing technique. In one embodiment, rectangular cross sectionspokes are cut such as by known laser cutting techniques from tubestock, a portion of which forms the hub 16.

The barrier 15 may comprise any of a variety of materials whichfacilitate cellular in-growth, such as ePTFE. The suitability ofalternate materials for barrier 15 can be determined through routineexperimentation by those of skill in the art. The barrier 15 may beprovided on either one or both axially facing sides of the occlusionmember. In one embodiment, the barrier 15 comprises two layers, with onelayer on each side of the frame 14. The two layers may be bonded to eachother around the spokes 17 in any of a variety of ways, such as by heatbonding with or without an intermediate bonding layer such aspolyethylene or FEP, adhesives, sutures, and other techniques which willbe apparent to those of skill in the art in view of the disclosureherein. The barrier 15 preferably has a thickness of no more than about0.003″ and a porosity within the range of from about 5 μm to about 60μm.

The barrier 15 in one embodiment preferably is securely attached to theframe 14 and retains a sufficient porosity to facilitate cellularingrowth and/or attachment. One method of manufacturing a suitablecomposite membrane barrier 15 is illustrated in FIGS. 13-16. Asillustrated schematically in FIG. 13, a bonding layer 254 preferablycomprises a mesh or other porous structure having an open surface areawithin the range of from about 10% to about 90%. Preferably, the opensurface area of the mesh is within the range of from about 30% to about60%. The opening or pore size of the bonding layer 254 is preferablywithin the range of from about 0.005 inches to about 0.050 inches, and,in one embodiment, is about 0.020 inches. The thickness of the bondinglayer 254 can be varied widely, and is generally within the range offrom about 0.0005 inches to about 0.005 inches. In a preferredembodiment, the bonding layer 254 has a thickness of about 0.001 toabout 0.002 inches. One suitable polyethylene bonding mesh is availablefrom Smith and Nephew, under the code SN9.

Referring to FIG. 14, the bonding layer 254 is preferably placedadjacent one or both sides of a spoke or other frame element 14. Thebonding layer 254 and frame 14 layers are then positioned in-between afirst membrane 250 and a second membrane 252 to provide a compositemembrane stack. The first membrane 250 and second membrane 252 maycomprise any of a variety of materials and thicknesses, depending uponthe desired functional result. Generally, the membrane has a thicknesswithin the range of from about 0.0005 inches to about 0.010 inches. Inone embodiment, the membranes 250 and 252 each have a thickness on theorder of from about 0.001 inches to about 0.002 inches, and compriseporous ePTFE, having a porosity within the range of from about 10microns to about 100 microns.

The composite stack is heated to a temperature of from about 200° toabout 300°, for about 1 minute to about 5 minutes under pressure toprovide a finished composite membrane assembly with an embedded frame 14as illustrated schematically in FIG. 15. The final composite membranehas a thickness within the range of from about 0.001 inches to about0.010 inches, and, preferably, is about 0.002 to about 0.003 inches inthickness. However, the thicknesses and process parameters of theforegoing may be varied considerably, depending upon the materials ofthe bonding layer 254 the first layer 250 and the second layer 252.

As illustrated in top plan view in FIG. 16, the resulting finishedcomposite membrane has a plurality of “unbonded” windows or areas 256suitable for cellular attachment and/or ingrowth. The attachment areas256 are bounded by the frame 14 struts, and the cross-hatch or otherwall pattern formed by the bonding layer 254. Preferably, a regularwindow 256 pattern is produced in the bonding layer 254.

The foregoing procedure allows the bonding mesh to flow into the firstand second membranes 250 and 252 and gives the composite membrane 15greater strength (both tensile and tear strength) than the componentswithout the bonding mesh. The composite allows uniform bonding whilemaintaining porosity of the membrane 15, to facilitate tissueattachment. By flowing the thermoplastic bonding layer into the pores ofthe outer mesh layers 250 and 252, the composite flexibility ispreserved and the overall composite layer thickness can be minimized.

Referring back to FIGS. 1 and 2, the occlusion device 10 may be furtherprovided with a bulking element or stabilizer 194. The stabilizer 194may be spaced apart along an axis from the occluding member 11. In theillustrated embodiment, a distal end 190 and a proximal end 192 areidentified for reference. The designation proximal or distal is notintended to indicate any particular anatomical orientation or deploymentorientation within the deployment catheter. As shown in FIGS. 1 and 2,the stabilizer 194 is spaced distally apart from the occluding member11.

For use in the LAA, the occluding member 11 has an expanded diameterwithin the range of from about 1 cm to about 5 cm, and, in oneembodiment, about 3 cm. The axial length of the occluding member 11 inan expanded, unstressed orientation from the distal end 192 to the hub16 is on the order of about 1 cm. The overall length of the occlusiondevice 10 from the distal end 192 to the proximal end 190 is within therange of from about 1.5 cm to about 4 cm and, in one embodiment, about2.5 cm. The axial length of the stabilizer 194 between distal hub 191and proximal hub 16 is within the range of from about 0.5 cm to about 2cm, and, in one embodiment, about 1 cm. The expanded diameter of thestabilizer 194 is within the range of from about 0.5 cm to about 2.5 cm,and, in one embodiment, about 1.4 cm. The outside diameter of the distalhub 191 and proximal hub 16 is about 2.5 mm.

Preferably, the occlusion device 10 is provided with one or moreretention structures for retaining the device in the left atrialappendage or other body cavity or lumen. In the illustrated embodiment,a plurality of barbs or other anchors 195 are provided, for engagingadjacent tissue to retain the occlusion device 10 in its implantedposition and to limit relative movement between the tissue and theocclusion device. The illustrated anchors are provided on one or more ofthe spokes 17, or other portion of frame 14. Preferably, every spoke,every second spoke or every third spoke are provided with one or two ormore anchors each.

The illustrated anchor is in the form of a barb, with one on each spokefor extending into tissue at or near the opening of the LAA. Dependingupon the embodiment, two or three barbs may alternatively be desired oneach spoke. In the single barb embodiment of FIG. 7, each barb isinclined in a proximal direction. This is to inhibit proximal migrationof the implant out of the left atrial appendage. In this context, distalrefers to the direction into the left atrial appendage, and proximalrefers to the direction from the left atrial appendage into the heart.

Alternatively, one or more barbs may face distally, to inhibit distalmigration of the occlusion device deeper into the LAA. Thus the implantmay be provided with at least one proximally facing barb and at leastone distally facing barb. For example, in an embodiment of the typeillustrated in FIG. 12, discussed below, a proximal plurality of barbsmay be inclined in a first direction, and a distal plurality of barbsmay be inclined in a second direction, to anchor the implant againstboth proximal and distal migration.

One or more anchors 195 may also be provided on the stabilizer 194, suchthat it assists not only in orienting the occlusion device 10 andresisting compression of the LAA, but also in retaining the occlusiondevice 10 within the LAA. Any of a wide variety of structures may beutilized for anchor 195, either on the occluding member 11 or thestabilizer 194 or both, such as hooks, barbs, pins, sutures, adhesives,ingrowth surfaces and others which will be apparent to those of skill inthe art in view of the disclosure herein.

In use, the occlusion device 10 is preferably positioned within atubular anatomical structure to be occluded such as the left atrialappendage. In a left atrial appendage application, the occluding member11 is positioned across or near the opening to the LAA and thestabilizer 194 is positioned within the LAA. The stabilizer 194 assistsin the proper location and orientation of the occluding member 11, aswell as resists compression of the LAA behind the occluding member 11.The present inventors have determined that following deployment of anoccluding member 11 without a stabilizer 194 or other bulking structureto resist compression of the LAA, normal operation of the heart maycause compression and resulting volume changes in the LAA, therebyforcing fluid past the occluding member 11 and inhibiting or preventinga complete seal. Provision of a stabilizer 194 dimensioned to preventthe collapse or pumping of the LAA thus minimizes leakage, and provisionof the barbs facilitates endothelialization or other cell growth acrossthe occluding member 11.

The stabilizer 194 is preferably movable between a reducedcross-sectional profile for transluminal advancement into the leftatrial appendage, and an enlarged cross-sectional orientation asillustrated to fill or to substantially fill a cross-section through theLAA. The stabilizing member may enlarge to a greater cross section thanthe (pre-stretched) anatomical cavity, to ensure a tight fit andminimize the likelihood of compression. One convenient constructionincludes a plurality of elements 196 which are radially outwardlyexpandable in response to axial compression of a distal hub 191 towardsa proximal hub 16. Elements 196 each comprise a distal segment 198 and aproximal segment 202 connected by a bend 200. The elements 196 may beprovided with a bias in the direction of the radially enlargedorientation as illustrated in FIG. 2, or may be radially expanded byapplying an expansion force such as an axially compressive force betweendistal hub 191 and proximal hub 16 or a radial expansion force such asmight be applied by an inflatable balloon. Elements 196 may convenientlybe formed by laser cutting the same tube stock as utilized to constructthe distal hub 191, proximal hub 16 and frame 14, as will be apparent tothose of skill in the art in view of the disclosure herein.Alternatively, the various components of the occlusion device 10 may beseparately fabricated or fabricated in subassemblies and securedtogether during manufacturing.

As a post implantation step for any of the occlusion devices disclosedherein, a radiopaque dye or other visualizable media may be introducedon one side or the other of the occlusion device, to permitvisualization of any escaped blood or other fluid past the occlusiondevice. For example, in the context of a left atrial appendageapplication, the occlusion device may be provided with a central lumenor other capillary tube or aperture which permits introduction of avisualizable dye from the deployment catheter through the occlusiondevice and into the entrapped space on the distal side of the occlusiondevice. Alternatively, dye may be introduced into the entrapped spacedistal to the occlusion device such as by advancing a small gauge needlefrom the deployment catheter through the barrier 15 on the occlusiondevice, to introduce dye.

Modifications to the occlusion device 10 are illustrated in FIGS. 3-4.The occlusion device 10 comprises an occlusion member 11 and astabilizing member 194 as previously discussed. In the presentembodiment, however, each of the distal segments 198 inclines radiallyoutwardly in the proximal direction and terminates in a proximal end204. The proximal end 204 may be provided with an atraumaticconfiguration, for pressing against, but not penetrating, the wall ofthe left atrial appendage or other tubular body structure. Three or moredistal segments 198 are preferably provided, and generally anywherewithin the range of from about 6 to about 20 distal segments 198 may beused. In one embodiment, 9 distal segments 198 are provided. In thisembodiment, three of the distal segments 198 have an axial length ofabout 5 mm, and 6 of the distal segments 198 have an axial length ofabout 1 cm. Staggering the lengths of the distal segments 198 mayaxially elongate the zone in the left atrial appendage against which theproximal ends 204 provide anchoring support for the occlusion device.

The occlusion device 10 illustrated in FIGS. 3 and 4 is additionallyprovided with a hinge 206 to allow the longitudinal axis of theocclusion member 11 to be angularly oriented with respect to thelongitudinal axis of the stabilizing member 194. In the illustratedembodiment, the hinge 206 is a helical coil, although any of a varietyof hinge structures can be utilized. The illustrated embodiment may beconveniently formed by laser cutting a helical slot through a section ofthe tube from which the principal structural components of the occlusiondevice 10 are formed. At the distal end of the hinge 206, an annularband 208 connects the hinge 206 to a plurality of axially extendingstruts 210. In the illustrated embodiment, three axial struts 210 areprovided, spaced equilaterally around the circumference of the body.Axial struts 210 may be formed from a portion of the wall of theoriginal tube stock, which portion is left in its original axialorientation following formation of the distal segments 198 such as bylaser cutting from the tubular wall.

The occlusion member 11 is provided with a proximal zone 212 on each ofthe spokes 17. Proximal zone 212 has an enhanced degree of flexibility,to accommodate the fit between the occlusion member 11 and the wall ofthe left atrial appendage. Proximal section 212 may be formed byreducing the cross sectional area of each of the spokes 17, which may beprovided with a wave pattern as illustrated.

Each of the spokes 17 terminates in a proximal point 214. Proximal point214 may be contained within layers of the barrier 15, or may extendthrough or beyond the barrier 15 such as to engage adjacent tissue andassist in retaining the occlusion device 10 at the deployment site.

Referring to FIGS. 5 and 6, a further variation on the occlusion device10 illustrated in FIGS. 1 and 2 is provided. The occlusion device 10 isprovided with a proximal face 216 on the occlusion member 11, instead ofthe open and proximally concave face on the embodiment of FIGS. 1 and 2.The proximal face 216 is formed by providing a proximal spoke 218connects at an apex 220 to some or all of the distal spokes 17. Theproximal spoke 218, and corresponding apex 220 and distal spoke 17 maybe an integral structure, such as a single ribbon or wire, or elementcut from a tube stock as has been discussed.

Proximal spokes 218 are each attached to a hub 222 at the proximal end192 of the occlusion device 10. The barrier 15 may surround either theproximal face or the distal face or both on the occlusion member 11. Ingeneral, provision of a proximal spoke 218 connected by an apex 220 to adistal spoke 17 provides a greater radial force than a distal spoke 17alone, which will provide an increased resistance to compression if theocclusion member 11 is positioned with the LAA.

Referring to FIGS. 7-12, alternate structures of the occlusion device inaccordance with the present invention are illustrated. In general, theocclusion device 10 comprises an occluding member but does not include adistinct stabilizing member as has been illustrated in connection withprevious embodiments. Any of the embodiments previously disclosed hereinmay also be constructed using the occluding member only, and omittingthe stabilizing member as will be apparent to those of skill in the artin view of the disclosure herein.

The occluding device 10 comprises a proximal end 192, a distal end 190,and a longitudinal axis extending therebetween. A plurality of supports228 extend between a proximal hub 222 and a distal hub 191. At least twoor three supports 228 are provided, and preferably at least about ten.In one embodiment, sixteen supports 228 are provided. However, theprecise number of supports 228 can be modified, depending upon thedesired physical properties of the occlusion device 10 as will beapparent to those of skill in the art in view of the disclosure herein,without departing from the present invention.

Each support 228 comprises a proximal spoke portion 218, a distal spokeportion 17, and an apex 220 as has been discussed. Each of the proximalspoke portion 218, distal spoke portion 17 and apex 220 may be a regionon an integral support 228, such as a continuous rib or frame memberwhich extends in a generally curved configuration as illustrated with aconcavity facing towards the longitudinal axis of the occlusion device10. Thus, no distinct point or hinge at apex 220 is necessarilyprovided.

At least some of the supports 228, and, preferably, each support 228, isprovided with one or two or more barbs 195. In the illustratedconfiguration, the occlusion device 10 is in its enlarged orientation,such as for occluding a left atrial appendage or other body cavity orlumen. In this orientation, each of the barbs 195 projects generallyradially outwardly from the longitudinal axis, and is inclined in theproximal direction. One or more barbs may also be inclined distally, asis discussed elsewhere herein. In an embodiment where the barbs 195 andcorresponding support 228 are cut from a single ribbon, sheet or tubestock, the barb 195 will incline radially outwardly at approximately atangent to the curve formed by the support 228.

The occlusion device 10 constructed from the frame illustrated in FIG. 7may be constructed in any of a variety of ways, as will become apparentto those of skill in the art in view of the disclosure herein. In onemethod, the occlusion device 10 is constructed by laser cutting a pieceof tube stock to provide a plurality of axially extending slotsin-between adjacent supports 228. Similarly, each barb 195 can be lasercut from the corresponding support 228 or space in-between adjacentsupports 228. The generally axially extending slots which separateadjacent supports 228 end a sufficient distance from each of theproximal end 192 and distal end 190 to leave a proximal hub 222 and adistal hub 191 to which each of the supports 228 will attach. In thismanner, an integral cage structure may be formed. Alternatively, each ofthe components of the cage structure may be separately formed andattached together such as through soldering, brazing, heat bonding,adhesives, and other fastening techniques which are known in the art. Afurther method of manufacturing the occlusion device 10 is to laser cuta slot pattern on a flat sheet of appropriate material, such as aflexible metal or polymer, as has been discussed in connection withprevious embodiments. The flat sheet may thereafter be rolled about anaxis and opposing edges bonded together to form a tubular structure.

The apex portion 220 which carries the barb 195 may be advanced from alow profile orientation in which each of the supports 228 extendgenerally parallel to the longitudinal axis, to an implanted orientationas illustrated, in which the apex 220 and the barb 195 are positionedradially outwardly from the longitudinal axis. The support 228 may bebiased towards the enlarged orientation, or may be advanced to theenlarged orientation under positive force following positioning withinthe tubular anatomical structure, in any of a variety of manners.

For an example of enlarging under positive force, referring to FIG. 8,an inflatable balloon 230 is positioned within the occlusion device 10.Inflatable balloon 230 is connected by way of a, removable coupling 232to an inflation catheter 234. Inflation catheter 234 is provided with aninflation lumen for providing communication between an inflation mediasource 236 outside of the patient and the balloon 230. Followingpositioning within the target body lumen, the balloon 230 is inflated,thereby engaging barbs 195 with the surrounding tissue. The inflationcatheter 234 is thereafter removed, by decoupling the removable coupling232, and the inflation catheter 234 is thereafter removed. The balloon230 may be either left in place within the occlusion device 10, ordeflated and removed by the inflation catheter 234.

In an alternate embodiment, the supports 228 are radially enlarged suchas through the use of a deployment catheter 238. See FIG. 9. Deploymentcatheter 238 comprises a lumen for movably receiving a deploymentelement such as a flexible line 240. Deployment line 240 extends in aloop 244 formed by an aperture or slip knot 242. As will be apparentfrom FIG. 9, proximal retraction on the deployment line 240 whileresisting proximal movement of proximal hub 222 such as by using thedistal end of the catheter 238 will cause the distal hub 191 to be drawntowards the proximal hub 222, thereby radially enlarging thecross-sectional area of the occlusion device 10. Depending upon thematerial utilized for the occlusion device 10, the supports 228 willretain the radially enlarged orientation by elastic deformation, or maybe retained in the enlarged orientation such as by securing the slipknot 242 immovably to the deployment line 240 at the fully radiallyenlarged orientation. This may be accomplished in any of a variety ofways, using additional knots, clips, adhesives, or other techniquesknown in the art.

A variety of alternative structures may be utilized, to open or enlargethe occlusion device 10 under positive force. For example, Referring toFIG. 9, a pullwire 240 may be removably attached to the distal hub 191or other distal point of attachment on the occlusion device 10. Proximalretraction of the pullwire 240 while resisting proximal motion of theproximal hub 222 such as by using the distal end of the catheter 238will cause enlargement of the occlusion device 10 as has been discussed.The pullwire 240 may then be locked with respect to the proximal hub 222and severed or otherwise detached to enable removal of the deploymentcatheter 238 and proximal extension of the pullwire 240. Locking of thepullwire with respect to the proximal hub 222 may be accomplished in anyof a variety of ways, such as by using interference fit or friction fitstructures, adhesives, a knot or other technique depending upon thedesired catheter design.

Referring to FIGS. 10 and 11, the occlusion device 10 may be providedwith a barrier 15 such as a mesh or fabric as has been previouslydiscussed. Barrier 15 may be provided on only one hemisphere such asproximal face 216, or may be carried by the entire occlusion device 10from proximal end 192 to distal end 190. The barrier may be secured tothe radially inwardly facing surface of the supports 228, as illustratedin FIG. 11, or may be provided on the radially outwardly facing surfacesof supports 228, or both.

A further embodiment of the occlusion device 10 is illustrated in FIG.12, in which the apex 220 is elongated in an axial direction to provideadditional contact area between the occlusion device 10 and the wall ofthe tubular structure. In this embodiment, one or two or three or moreanchors 195 may be provided on each support 228, depending upon thedesired clinical performance. The occlusion device 10 illustrated inFIG. 12 may also be provided with any of a variety of other featuresdiscussed herein, such as a partial or complete barrier 15. In addition,the occlusion device 10 illustrated in FIG. 12 may be enlarged using anyof the techniques disclosed elsewhere herein.

Referring to FIG. 17, there is schematically illustrated a furtheraspect of the present invention. An adjustable implant deployment system300 comprises generally a catheter 302 for placing a detachable implant304 within a body cavity or lumen, as has been discussed. The catheter302 comprises an elongate flexible tubular body 306, extending between aproximal end 308 and a distal end 310. The catheter is shown in highlyschematic form, for the purpose of illustrating the functional aspectsthereof. The catheter body will have a sufficient length and diameter topermit percutaneous entry into the vascular system, and transluminaladvancement through the vascular system to the desired deployment site.For example, in an embodiment intended for access at the femoral arteryand deployment within the left atrial appendage, the catheter 302 willhave a length within the range of from about 50 cm to about 150 cm, anda diameter of generally no more than about 15 French. Further dimensionsand physical characteristics of catheters for navigation to particularsites within the body are well understood in the art and will not befurther described herein.

The tubular body 306 is further provided with a handle 309 generally onthe proximal end 308 of the catheter 302. The handle 309 permitsmanipulation of the various aspects of the implant deployment system300, as will be discussed below. Handle 309 may be manufactured in anyof a variety of ways, typically by injection molding or otherwiseforming a handpiece for single-hand operation, using materials andconstruction techniques well known in the medical device arts.

The implant 304 may be in the form of any of those described previouslyherein, as modified below. In general, the implant is movable from areduced crossing profile to an enlarged crossing profile, such that itmay be positioned within a body structure and advanced from its reducedto its enlarged crossing profile to obstruct bloodflow or perform otherfunctions while anchored therein. The implant 304 may be biased in thedirection of the enlarged crossing profile, may be neutrally biased ormay be biased in the direction of the reduced crossing profile. Anymodifications to the device and deployment system to accommodate thesevarious aspects of the implant 304 may be readily accomplished by thoseof skill in the art in view of the disclosure herein.

In the illustrated embodiment, the distal end 314 of the implant 304 isprovided with an implant plug 316. Implant plug 316 provides a stoppingsurface 317 for contacting an axially movable core 312. The core 312extends axially throughout the length of the catheter body 302, and isattached at its proximal end to a core control 332 on the handle 309.

The core 312 may comprise any of a variety of structures which hassufficient lateral flexibility to permit navigation of the vascularsystem, and sufficient axial column strength to enable reduction of theimplant 304 to its reduced crossing profile. Any of a variety ofstructures such as hypotube, solid core wire, “bottomed out” coil springstructures, or combinations thereof may be used, depending upon thedesired performance of the finished device. In one embodiment, the core312 comprises stainless steel tubing.

The distal end of core 312 is positioned within a recess or lumen 322defined by a proximally extending guide tube 320. In the illustratedembodiment, the guide tube 320 is a section of tubing such as metalhypotube, which is attached at the distal end 314 of the implant andextends proximally within the implant 304. The guide tube 320 preferablyextends a sufficient distance in the proximal direction to inhibitbuckling or prolapse of the core 312 when distal pressure is applied tothe core control 332 to reduce the profile of the implant 304. However,the guide tube 320 should not extend proximally a sufficient distance tointerfere with the opening of the implant 304.

As will be appreciated by reference to FIG. 17, the guide tube 320 mayoperate as a limit on distal axial advancement of the proximal end 324of implant 304. Thus, the guide tube 320 preferably does not extendsufficiently far proximally from the distal end 314 to interfere withoptimal opening of the implant 304. The specific dimensions aretherefore relative, and will be optimized to suit a particular intendedapplication. In one embodiment, the implant 304 has an implanted outsidediameter within the range of from about 5 mm to about 45 mm, and anaxial implanted length within the range of from about 5 mm to about 45mm. The guide tube 320 has an overall length of about 3 mm to about 35mm, and an outside diameter of about 0.095 inches.

An alternate guide tube 320 is schematically illustrated in FIG. 18. Inthis configuration, the guide tube 320 comprises a plurality of tubularsegments 321 spaced apart by an intervening space 323. This allowsincreased flexibility of the guide tube 320, which may be desirableduring the implantation step, while retaining the ability of the guidetube 320 to maintain linearity of the core 312 while under axialpressure. Although three segments 321 are illustrated in FIG. 18, asmany as 10 or 20 or more segments 321 may be desirable depending uponthe desired flexibility of the resulting implant.

Each adjacent pair of segments 321 may be joined by a hinge element 325which permits lateral flexibility. In the illustrated embodiment, thehinge element 325 comprises an axially extending strip or spine, whichprovides column strength along a first side of the guide tube 320. Theguide tube 320 may therefore be curved by compressing a second side ofthe guide tube 320 which is generally offset from the spine 325 by about180°. A limit on the amount of curvature may be set by adjusting theaxial length of the space 323 between adjacent segments 321. In anembodiment having axial spines 325, each axial spine 325 may berotationally offset from the next adjacent axial spine 325 to enableflexibility of the overall guide tube 320 throughout a 360° angularrange of motion.

Alternatively, the flexible hinge point between each adjacent segment321 may be provided by cutting a spiral groove or plurality of parallelgrooves in a tubular element in between what will then become eachadjacent pair of segments 321. In this manner, each tubular element 321will be separated by an integral spring like structure, which can permitflexibility. As a further alternative, the entire length of the guidetube 320 may comprise a spring. Each of the forgoing embodiments may bereadily constructed by laser cutting or other cutting from a piece oftube stock, to produce a one piece guide tube 320. Alternatively, theguide tube 320 may be assembled from separate components and fabricatedtogether using any of a variety of bonding techniques which areappropriate for the construction material selected for the tube 320.

Various distal end 314 constructions may be utilized, as will beapparent to those of skill in the art in view of the disclosure herein.In the illustrated embodiment, the distal implant plug 316 extendswithin the implant 304 and is attached to the distal end of the guidetube 320. The implant plug 316 may be secured to the guide tube 320 andimplant 304 in any of a variety of ways, depending upon the variousconstruction materials. For example, any of a variety of metal bondingtechniques such as a welding, brazing, interference fit such as threadedfit or snap fit, may be utilized. Alternatively, any of a variety ofbonding techniques for dissimilar materials may be utilized, such asadhesives, and various molding techniques. In one construction, theimplant plug 316 comprises a molded polyethylene cap, and is held inplace utilizing a distal cross pin 318 which extends through the implant304, the guide tube 320 and the implant plug 316 to provide a secure fitagainst axial displacement.

The proximal end 324 of the implant 304 is provided with a releasablelock 326 for attachment to a release element such as pull wire 328. Pullwire 328 extends proximally throughout the length of the tubular body306 to a proximal pull wire control 330 on the handle 309.

As used herein, the term pull wire is intended to include any of a widevariety of structures which are capable of transmitting axial tension orcompression such as a pushing or pulling force with or without rotationfrom the proximal end 308 to the distal end 310 of the catheter 302.Thus, monofilament or multifilament metal or polymeric rods or wires,woven or braided structures may be utilized. Alternatively, tubularelements such as a concentric tube positioned within the outer tubularbody 306 may also be used as will be apparent to those of skill in theart.

In the illustrated embodiment, the pull wire 328 is releasably connectedto the proximal end 324 of the implant 304. This permits proximaladvancement of the proximal end of the implant 304, which cooperateswith a distal retention force provided by the core 312 against thedistal end of the implant to axially elongate the implant 304 therebyreducing it from its implanted configuration to its reduced profile forimplantation. The proximal end of the pull wire 328 may be connected toany of a variety of pull wire controls 330, including rotational knobs,levers and slider switches, depending upon the design preference.

The proximal end 324 of the implant 304 is thus preferably provided witha releasable lock 326 for attachment of the pullwire 328 to thedeployment catheter. In the illustrated embodiment, the releasable lockis formed by advancing the pullwire distally around a cross pin 329, andproviding an eye or loop which extends around the core 312. As long asthe core 312 is in position within the implant 304, proximal retractionof the pullwire 328 will advance the proximal end 324 of the implant 304in a proximal direction. See FIG. 17A. However, following deployment,proximal retraction of the core 312 such as by manipulation of the corecontrol 332 will pull the distal end of the core 312 through the loop onthe distal end of the pullwire 328. The pullwire 328 may then be freelyproximally removed from the implant 304, thereby enabling detachment ofthe implant 304 from the deployment system 300 within a treatment site.See FIG. 17B.

The implant deployment system 300 thus permits the implant 304 to bemaintained in a low crossing profile configuration, to enabletransluminal navigation to a deployment site. Following positioning ator about the desired deployment site, proximal retraction of the core312 enables the implant 304 to radially enlarge under its own bias tofit the surrounding tissue structure. Alternatively, the implant can beenlarged under positive force, such as by inflation of a balloon or by amechanical mechanism as is discussed elsewhere herein. Once theclinician is satisfied with the position of the implant 304, such as byinjection of dye and visualization using conventional techniques, thecore 312 is proximally retracted thereby releasing the lock 326 andenabling detachment of the implant 304 from the deployment system 300.

If, however, visualization reveals that the implant 304 is not at thelocation desired by the clinician, proximal retraction of the pull wire328 with respect to the core 312 will radially reduce the diameter ofthe implant 304, thereby enabling repositioning of the implant 304 atthe desired site. Thus, the present invention permits the implant 304 tobe enlarged or reduced by the clinician to permit repositioning and/orremoval of the implant 304 as may be desired.

In an alternate construction, the implant may be radially enlarged orreduced by rotating a torque element extending throughout the deploymentcatheter. Referring to FIG. 19, the elongate flexible tubular body 306of the deployment catheter 302 includes a rotatable torque rod 340extending axially therethrough. The proximal end of the torque rod 340may be connected at a proximal manifold to a manual rotation device suchas a hand crank, thumb wheel, rotatable knob or the like. Alternatively,the torque rod 340 may be connected to a power driven source ofrotational energy such as a motor drive or air turbine.

The distal end of the torque rod 340 is integral with or is connected toa rotatable core 342 which extends axially through the implant 304. Adistal end 344 of the rotatable core 342 is positioned within a cavity322 as has been discussed.

The terms torque rod or torque element are intended to include any of awide variety of structures which are capable of transmitting arotational torque throughout the length of a catheter body. For example,solid core elements such as stainless steel, nitinol or other nickeltitanium alloys, or polymeric materials may be utilized. In anembodiment intended for implantation over a guide-wire, the torque rod340 is preferably provided with an axially extending central guidewirelumen. This may be accomplished by constructing the torque rod 340 froma section of hypodermic needle tubing, having an inside diameter of fromabout 0.001 inches to about 0.005 inches or more greater than theoutside diameter of the intended guidewire. Tubular torque rods 340 mayalso be fabricated or constructed utilizing any of a wide variety ofpolymeric constructions which include woven or braided reinforcinglayers in the wall. Torque transmitting tubes and their methods ofconstruction are well understood in the intracranial access androtational atherectomy catheter arts, among others, and are notdescribed in greater detail herein. Use of a tubular torque rod 340 alsoprovides a convenient infusion lumen for injection of contrast mediawithin the implant 304, such as through a port 343.

The proximal end 324 of the implant 304 is provided with a threadedaperture 346 through which the core 342 is threadably engaged. As willbe appreciated by those of skill in the art in view of the disclosureherein, rotation of the threaded core 342 in a first direction relativeto the proximal end 324 of the implant 304 will cause the rotatable core342 to advance distally. This distal advancement will result in an axialelongation and radial reduction of the implantable device 304. Rotationof the rotatable core 342 in a reverse direction will cause a proximalretraction of the rotatable core 342, thus enabling a radial enlargementand axial shortening of the implantable device 304.

The deployment catheter 302 is further provided with an antirotationlock 348 between a distal end 350 of the tubular body 306 and theproximal end 324 of the implant 304. In general, the rotational lock 348may be conveniently provided by cooperation between a first surface 352on the distal end 350 of the deployment catheter 302, which engages asecond surface 354 on the proximal end 324 of the implantable device304, to rotationally link the deployment catheter 302 and theimplantable device 304. Any of a variety of complementary surfacestructures may be provided, such as an axial extension on one of thefirst and second surfaces for coupling with a corresponding recess onthe other of the first and second surfaces. Such extensions and recessesmay be positioned laterally offset from the axis of the catheter.Alternatively, they may be provided on the longitudinal axis with any ofa variety of axially releasable anti-rotational couplings having atleast one flat such as a hexagonal or other multifaceted cross sectionalconfiguration.

As schematically illustrated in FIG. 19, one or more projections 356 onthe first surface 352 may engage a corresponding recess 358 on thesecond surface 354. Any of a variety of alternative complementarysurface structures may also be provided, as will be apparent to those ofskill in the art in view of the disclosure herein. For example,referring to FIG. 19A, the projection 356 is in the form of an axiallyextending pin for engaging a complimentary recess 358 on the proximalend 324 of the implant 304. FIG. 19B illustrates an axially extendingspline 356 for receipt within a complimentary axially extending recess358. The various pin, spline and other structures may be reversedbetween the distal end of tubular body 306 and the proximal end 324 ofthe implant 304 as will be apparent to those of skill in the art in viewof the disclosure herein.

Upon placement of the implantable device 304 at the desired implantationsite, the torque rod 340 is rotated in a direction that produces anaxial proximal retraction. This allows radial enlargement of theradially outwardly biased implantable device 304 at the implantationsite. Continued rotation of the torque rod 340 will cause the threadedcore 342 to exit proximally through the threaded aperture 346. At thatpoint, the deployment catheter 302 may be proximally retracted from thepatient, leaving the implanted device 304 in place.

By modification of the decoupling mechanism to allow the core 342 to bedecoupled from the torque rod 340, the rotatable core 342 may be leftwithin the implantable device 304, as may be desired depending upon theintended deployment mechanism. For example, the distal end of the core342 may be rotatably locked within the end cap 326, such as by includingcomplimentary radially outwardly or inwardly extending flanges andgrooves on the distal end of the core 342 and inside surface of thecavity 322. In this manner, proximal retraction of the core 342 byrotation thereof relative to the implantable device 304 will pull theend cap 326 in a proximal direction under positive force. This may bedesirable as a supplement to or instead of a radially enlarging biasbuilt into the implantable device 304.

In the embodiment illustrated in FIG. 19, or any other of the deploymentand/or removal catheters described herein, the distal end of the tubularbody 306 may be provided with a zone or point of enhanced lateralflexibility. This may be desirable in order allow the implant to seat inthe optimal orientation within the left atrial appendage, and not berestrained by a lack of flexibility in the tubular body 306. This may beaccomplished in any of a variety of way, such as providing the distalmost one or two or three centimeters or more of the tubular body 306with a spring coil configuration. In this manner, the distal end of thetubular body 306 will be sufficiently flexible to allow the implant 304to properly seat within the LAA. This distal flex zone on the tubularbody 306 may be provided in any of a variety of ways, such as by cuttinga spiral slot in the distal end of the tubular body 306 using lasercutting or other cutting techniques. The components within the tubularbody 306 such as torque rod 340 may similarly be provided with a zone ofenhanced flexibility in the distal region of the tubular body 306.

The implantable device 304 may also be retrieved and removed from thebody in accordance with a further aspect of the present invention. Onemanner of retrieval and removal will be understood in connection withFIGS. 20 through 20 c. Referring to FIG. 20, a previously implanteddevice 304 is illustrated as releasably coupled to the distal end of thetubular body 306, as has been previously discussed. Coupling may beaccomplished by aligning the tubular body 306 with the proximal end 324of the deployed implant 304, under fluoroscopic visualization, anddistally advancing a rotatable core 342 through the threaded aperture346. Threadable engagement between the rotatable core 342 and aperture346 may thereafter be achieved, and distal advancement of core 342 willaxially elongate and radially reduce the implant 304.

The tubular body 306 is axially moveably positioned within an outertubular delivery or retrieval catheter 360. Catheter 360 extends from aproximal end (not illustrated) to a distal end 362. The distal end 362is preferably provided with a flared opening, such as by constructing aplurality of petals 364 for facilitating proximal retraction of theimplant 304 as will become apparent. Petals 364 may be constructed in avariety of ways, such as by providing axially extending slits in thedistal end 362 of the delivery catheter 360. In this manner, preferablyat least about three, and generally at least about four or five or sixpetals or more will be provided on the distal end 362 of the deliverycatheter 360. Petals 364 manufactured in this manner would reside in afirst plane, transverse to the longitudinal axis of the deliverycatheter 360, if each of such petals 364 were inclined at 90 degrees tothe longitudinal axis of the delivery catheter 360.

In one application of the invention, a second layer of petals 365 areprovided, which would lie in a second, adjacent plane if the petals 365were inclined at 90 degrees to the longitudinal axis of the deliverycatheter 360. Preferably, the second plane of petals 365 is rotationallyoffset from the first plane of petals 364, such that the second petals365 cover the spaces 367 formed between each adjacent pair of petals365. The use of two or more layers of staggered petals 364 and 365 hasbeen found to be useful in retrieving implants 304, particularly whenthe implant 304 carries a plurality of tissue anchors 195.

The petals 364 and 365 may be manufactured from any of a variety ofpolymer materials useful in constructing medical device components suchas the delivery catheter 360. This includes, for example, polyethylene,PET, PEEK, PEBAX, and others well known in the art. The second petals365 may be constructed in any of a variety of ways. In one convenientconstruction, a section of tubing which concentrically fits over thedelivery catheter 360 is provided with a plurality of axially extendingslots in the same manner as discussed above. The tubing with a slotteddistal end may be concentrically positioned on the catheter 360, androtated such that the space between adjacent petals 365 is offset fromthe space between adjacent petals 364. The hub of the petals 365 maythereafter be bonded to the catheter 360, such as by heat shrinking,adhesives, or other bonding techniques known in the art.

The removal sequence will be further understood by reference to FIGS. 20a through 20 c. Referring to FIG. 20 a, the radially reduced implant 304is proximally retracted part way into the delivery catheter 360. Thiscan be accomplished by proximally retracting the tubular body 306 and/ordistally advancing the catheter 360. As illustrated in FIG. 20 b, thetubular body 306 having the implant 304 attached thereto is proximallyretracted a sufficient distance to position the tissue anchors 195within the petals 364. The entire assembly of the tubular body 306,within the delivery catheter 360 may then be proximally retracted withinthe transeptal sheath 366 or other tubular body as illustrated in FIG.20 c. The collapsed petals 364 allow this to occur while preventingengagement of the tissue anchors 195 with the distal end of thetranseptal sheath 366 or body tissue. The entire assembly having theimplantable device 304 contained therein may thereafter be proximallywithdrawn from or repositioned within the patient.

While particular forms of the invention have been described, it will beapparent that various modifications can be made without departing fromthe spirit and scope of the invention. Accordingly, it is not intendedthat the invention be limited, except as by the appended claims.

1. An implantable device for positioning within the left atrialappendage of a patient, comprising: an implant having a proximal hub, adistal hub, an intermediate hub and a longitudinal axis extendingtherebetween, the implant having a collapsed configuration and anexpanded configuration; a release element and a first receiving portionon the proximal hub of the implant sized and configured to releasablycouple the implant to the release element; wherein relative movementbetween the proximal hub and the distal hub of the implant causes theimplant to move either from its collapsed configuration to its expandedconfiguration, or from its expanded configuration to its collapsedconfiguration, and wherein the implant comprises a first apex portionbetween the proximal hub and said intermediate hub and a second apexportion between said intermediate hub and said distal hub, the implantin its expanded configuration increasing radially in dimension from theproximal hub to the first apex portion and then decreasing radially indimension from the first apex portion to the intermediate hub; andincreasing radially in dimension from the intermediate hub to the secondapex portion and then decreasing radially in dimension from the secondapex portion to the distal hub; wherein said first apex portion has alarger diameter than said second apex portion; and a barrier permittingblood flow within the implant and attached to the implant proximal theintermediate hub, the barrier having a porosity within the range of fromabout 10 microns to about 100 microns.
 2. The implantable device ofclaim 1 further comprising a set of barbs positioned on said first apexportion for interacting with the tissue of said left atrial appendage.3. The implantable device of claim 1 wherein the implant comprises aframe element and the barrier at least in part comprises a firstmembrane on a first side of the frame element, a second membrane on thesecond side of the frame element and a bonding layer for bonding thefirst and second membranes togetheter.
 4. The implantable device ofclaim 3 wherein the bonding layer comprises a porous structure having anopen surface area within the range of from about 10% to about 90% open.5. The implantable device of claim 3 wherein the frame element comprisesa plurality of radially outwardly extending spokes.
 6. The implantabledevice of claim 1 further comprising an elongate core and a secondreceiving portion on the distal end of the implant sized and configuredto receive and prevent distal advancement of the elongate core past thedistal end of the implant, the elongate core movable proximally from theimplant, and wherein the implant is biased to the expandedconfiguration.
 7. The implantable device of claim 6 further comprising arelease element having a distal element disposed within the implant, therelease element configured and attached to the implant such that therelease element is movable proximally from the implant after theelongate core is moved proximally from the implant.
 8. The implantabledevice of claim 7 wherein the release element distal end is loopedaround the core.
 9. The implantable device of claim 8 further comprisinga pin disposed in the receiving element, the release element disposed ononly one side of the pin.
 10. The implantable device of claim 6 whereinthe second receiving portion comprises a guide tube having a closeddistal end for non-fixedly receiving the core.